Mark Berry August 4, 2016
A Windows Server 2012R2 Essentials machine was returning strange results when I did a DNS query from PowerShell. I traced it back to modifications that 3CX version 14 had made to the Windows hosts file.More...
Mark Berry February 25, 2013
On my Server 2012 Essentials virtual machine, I was getting five or six messages every day telling me that the server is not connected to the Internet, even though it is. The messages appeared in a balloon alert in my system tray (from the 2012 Essentials Launchpad) as well as in the event log:More...
Mark Berry September 20, 2012
When you export a DNS zone from Go Daddy, there is some unusual formatting. IF you don’t fix it before importing it into DNS Made Easy (and probably other hosts), you may find that DNS queries are not resolving as expected. In my case, that meant email was not getting through.More...
Mark Berry September 19, 2012
After the Go Daddy DNS meltdown earlier this month, and since they do not allow secondary DNS unless you pay them, I’m experimenting with using DNS Made Easy for my primary DNS and BuddyNS for my secondary DNS. (At $30 yearly, a 10-domain DNS Made Easy account is less expensive than adding Go Daddy’s Premium DNS for $36/year.)
DNS Made Easy has lots of name servers hidden behind their six name server IP addresses, but even they can be affected by a DDoS attack (as there were in 2010). Theoretically, by using two DNS providers, if one goes down, at least half of the DNS queries to my domain will still be resolved by the other provider.More...
Mark Berry September 20, 2009
Occasionally on my Windows XP Pro SP3 machine, Outlook 2007 SP2 will tell me that it has had an error receiving POP mail from my SBS 2003 server, which resides on the same network.
I started a command prompt and typed “ping myserver.mydomain.local”. Sure enough, I get back the message “Ping request could not find host myserver.mydomain.local. Please check the name and try again.”
An nslookup works fine, so I know the SBS server is there and is responding to DNS requests.
In fact, I can “ping myserver” without problems. But for some reason, pinging the fully-qualified internal name doesn’t work.
Sometimes, I can just type “ipconfig /flushdns” to clear this up. Today that didn’t work. However once I actually stopped and started the DNS cache, ping started working and so did email:
net stop DNScache
net start DNScache
Mark Berry September 12, 2007
The Only Thing Constant is Change
On January 29, 2004, the the IP address for the DNS root hint for b.root-servers.net changed to 220.127.116.11:
Copy from Server Doesn't Always Copy from Server
I was testing the DNS configuration on two Windows Server 2003 machines. One is R2 SP2; the other is SBS 2003 SP2. In the DNS server's properties, on the Root Hints tab, I clicked on the Copy from Server button and copied from 18.104.22.168 (a Level 3 DNS server). However, this did not update the address for b.root-servers.net; it still showed the old 22.214.171.124. So when I ran dcdiag /test:dns, it reported an error on accessing b.root-servers.net.
I tried removing b.root-servers.net and copying from 126.96.36.199. This time, b.root-servers.net showed up with IP Address “Unknown”. This is strange, since I can use nslookup against 188.8.131.52 and get the correct address for b.root-servers.net. Apparently 184.108.40.206 does not let you copy root hints, although no error is displayed.
Next I tried copying from my ISP's DNS server. This worked, but it did not replace the old IP address; it just added the new one.
The bottom line is that once you get your root hints set up, you'd better double-check them against the official list here.
Old DCDiag Raises False Alarms
Another “gotcha” I encountered is that the original DCDiag program in Windows Server 2003 Support Tools was telling me that all of my root hints were bad. Microsoft Support suggested updating to the SP2 version of Support Tools, which did in fact fix that problem.More...
Mark Berry July 5, 2007
A post in the Yahoo group mssmallbiz asked an interesting question: when DNS Forwarders are configured under SBS 2003, is there a way to get the secondary nameserver to automatically take over when the primary is unavailable?
Don’t Use Forwarders
The answer was simple: don’t use forwarders. Go to Start > Administrative Tools > DNS, go into the Properties for the server, go to the Forwarders tab, and click Remove until they are gone.
Do Use Root Hints
Then make sure the root hints are up to date. The poster suggested using Windows Update. I didn’t see root hints there, but I found a simple way to refresh them: in the DNS Properties, go to the Root Hints tab, click on Copy from Server, and enter 220.127.116.11 as the IP address to copy the hints from.
Posters seemed to think that relying solely on root hints is actually faster for resolving external DNS queries.
The instructions work for Windows Server 2003 as well as SBS 2003!
Update: copying root hints from 18.104.22.168 doens’t work. See this post for details and a solution.More...
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